Display screen or portion thereof with a graphical user interface



FIG. 1 is a front view of a display screen or portion thereof with a graphical user interface showing the present design;

FIG. 2 is a front view of another embodiment of a display screen or portion thereof with a graphical user interface showing the present design;

FIG. 3 is a front view of another embodiment of a display screen or portion thereof with a graphical user interface showing the present design;

FIG. 4 is a front view of another embodiment of a display screen or portion thereof with a graphical user interface showing the present design;

FIG. 5 is a front view of another embodiment of a display screen or portion thereof with a graphical user interface showing the present design;

FIG. 6 is a front view of another embodiment of a display screen or portion thereof with a graphical user interface showing the present design;

FIG. 7 is a front view of another embodiment of a display screen or portion thereof with a graphical user interface showing the present design; and,

FIG. 8 is a front view of another embodiment of a display screen or portion thereof with a graphical user interface showing the present design.

The broken lines show an electronic device with a display screen and form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with a graphical user interface, as shown and described. 